Mario Bros. 3: Reach the other side of the water:
If you have a hammer, you can use it in world 3 to take away some rocks. You can then take a boat to the other side of the water.

The Lost Levels: Extra life at the flagpole:
Before touching the flag at the end of a level, make sure your coin total is a multiple of 11. ( 00, 11, 22, 33, 44, 55, 66, 77, 88 or 99). Touch the flag when the last digit of your remaining time is the same number as your coin total and you'll receive a 1-Up.(For example, 55 coins and 275 time left, or 11 coins and 081 time left)

The Lost Levels: Accessing World 9:To go to World 9, you must reach World 8-4 without using any warp pipes. You will only have 1 life when you go to World 9. Also, when you beat 9-4, the game will restart to 9-1 until you lose your life.

The Lost Levels: How to access World A - D:
For every time you beat World 8-4, the game adds a star to the Super Mario Brothers 2 logo on the title screen. When you reach eight stars, go to the title screen and hold A and press START on the controller.

The Lost Levels: Infinite Lives:
-At the beginning of board 2-1 you must jump to the top of the three step stair case and move forward until you see the flying turtle. Bounce on the flying turtle once and it should begin to walk toward the stairs. Move Mario to the top of the first step and press jump as fast as possible on the turtle as soon as he lands on the second step.

The Lost Levels: Level A-1 Extra Lives:
After the 1-up mushroom at the top of the screen, there is a zig zag brick lay out with red and green koopas. Let green ones go by, then duck and smash the first four bricks on the lowest level. Next, trap a red koopa on the far left by destroying the second brick. Smash the fourth brick and jump to stand on the brick left between the two spaces you made. Finally, carefully jump on the trapped koopa.

The Lost Levels: Warp Back To World 1:
You must be in World 3-1 to warp back to World 1. Toward the end of the stage, jump onto the spring and fly over the flagpole. When you land, run forwards, and you'll find the warp pipe that leads to World 1.

The Lost Levels: Warp To World 2:
When you're in World 1-2, jump onto the bricks at the top and run forwards past the pipe to exit the stage. Keep running to find the warp pipe that takes you to World 2.

The Lost Levels: Warp To World 3:
You must be in World 1-2 to warp to World 3. When you reach an area that has a pipe, a few bricks, and a Steel-Shelled Koopa, hit the first brick on the left to make a beanstalk pop out. Climb up the beanstalk and run forward until you reach the warp pipe that takes you to World 3.

The Lost Levels: Warp To World 4:
You must be in World 1-2 to Warp to World 4. When you get to the moving platforms, jump onto the platform and get a running start to jump to the small brick ceiling. Then, jump again to the next brick ceiling. Continue until you see 2 pipes and go down the one on the far left. You will find a secret area with lava. Make sure that Mario or Luigi is small. Run under the small lava pit that's positioned under a brick wall and keep going until you see a pipe. Don't go down the pipe. Instead, look for a secret coin block that's located one space to the left of the lava pit. Then, get on the coin block and look for a coin block that's located one space to the right of the first coin block. Jump onto the next coin block and jump up onto the brick wall ceiling and find a Warp Zone that leads to World 4.

The Lost Levels: Warp To World 5:
You must be in World 8-1 to Warp to World 5. After passing the 3rd Hammer Bro, go down the next pipe you see that points upwards. You will go to a secret water area. Collect the coins and exit, then go up the stairs and you will see a pipe that leads you back to World 5.

The Lost Levels: Warp to World 6:
You need to be at least Super Mario to do this. Toward the end of World 5-1, when you see two rows of floating bricks past two Red Paratroopas, hit the rightmost brick of the top row to discover a vine. Smash the brick next to it and climb the vine. After going through the small bonus area, you will be dropped off on a pipe right next to a Warp Zone that leads to World Six.

The Lost Levels: Warp to World 7:
Near the end of world 5-2, when you encounter the trio of tiny elevators, try to go as high as you can while attempting to jump off the last elevator and reach the top of the ceiling. Continue to run right, making sure to jump when the ceiling ends, to eventually reach the Warp Zone for World 7.

The Lost Levels: Warp To World C:
When you are in World A-3, use the spring to get over the flagpole at the end of the stage, then run forwards until you reach a pipe leading to World C.

The Lost Levels: Warp To World D:
In World B-4, go to the very last pipe in the level next to a lava pit. Jump in the pipe and you will be taken to a Warp Zone area leading to World D.